<template>
  <div class="comment-container">
    <!-- 评论列表 -->
    <div class="cmt-list"
      :class=" isShow ? 'art-cmt-container-1' : 'art-cmt-container-2' ">
      <van-list
          v-model="loading"
          :finished="done"
          finished-text="劳资是有底线的"
          @load="pullUpLoadMoreFn"
          :immediate-check="false"
          offset="80"
        >
        <!-- 评论的 Item 项 -->
        <div class="cmt-item"
          v-for="obj in commentList"
          :key="obj.com_id">
          <!-- 头部区域 -->
          <div class="cmt-header">
            <!-- 头部左侧 -->
            <div class="cmt-header-left">
              <img :src="obj.aut_photo" :alt="obj.aut_name" class="avatar">
              <span class="uname">{{ obj.aut_name }}</span>
            </div>
            <!-- 头部右侧 -->
            <div class="cmt-header-right">
              <van-icon
                v-if="obj.is_liking"
                name="like" size="16" color="red"
                @click="likeOrDislikeFn(obj)"
                />
              <van-icon
                v-else
                name="like-o" size="16" color="gray"
                @click="likeOrDislikeFn(obj)"
                />
            </div>
          </div>
          <!-- 主体区域 -->
          <div class="cmt-body">
              {{ obj.content }}
          </div>
          <!-- 尾部区域 -->
          <div class="cmt-footer">{{ $timeAgo(obj.pubdate) }}</div>
        </div>
      </van-list>
    </div>
    <!-- 底部添加评论区域 - 1 -->
    <div class="add-cmt-box van-hairline--top" v-if="isShow">
      <van-icon name="arrow-left" size="0.48rem" @click="$router.go(-1)" />
      <div class="ipt-cmt-div" @click="isShow = false">发表评论</div>
      <div class="icon-box">
        <van-badge :content="totalCount" max="99">
          <van-icon
            name="comment-o"
            size="0.53333334rem"
            @click="scrollIntoViewFn"
            />
        </van-badge>
        <van-icon name="star-o" size="0.53333334rem" />
        <van-icon name="share-o" size="0.53333334rem" />
      </div>
    </div>

    <!-- 底部添加评论区域 - 2 -->
    <div class="cmt-box van-hairline--top" v-else>
      <textarea
        v-model.trim="content"
        v-jujiao
        placeholder="友善评论、理性发言、阳光心灵"
        @blur="blurFn"
        ></textarea>
      <van-button type="default" @click="publishFn">发布</van-button>
    </div>
  </div>
</template>

<script>
import {
  getCommentListAPI,
  likeCommentAPI, dislikeCommentAPI,
  publishCommentAPI
} from '@/api/article'
export default {
  name: 'Comment',
  data () {
    return {
      commentList: [], // 评论列表
      isShow: true, // 控制发布评论第一套结构的可见性，默认值是true
      totalCount: null, // 评论数量
      content: '', // 评论的内容
      loading: false, // 控制每一页的家在状态
      done: false // 控制整个上拉的加载状态
    }
  },
  async activated () {
    this.getCommentListFn()
  },
  // 组件切走了，重置数据为初始值（与data中的初始值保持一致）
  deactivated () {
    this.commentList = []
    this.loading = false
    this.done = false
    this.totalCount = null
  },
  methods: {
    // 获取评论列表
    async getCommentListFn () {
      const resp = await getCommentListAPI({
        artId: this.$route.query.art_id,
        offset: this.lastId
      })
      const { results, total_count: total, last_id: lastId } = resp.data
      if (lastId === null || results.length === 0) {
        this.done = true
        return
      }
      this.lastId = lastId
      this.commentList = [...this.commentList, ...results]
      this.totalCount = total || null
      this.loading = false
    },
    // 评论点赞或取赞
    async likeOrDislikeFn (obj) {
      try {
        obj.is_liking ? await dislikeCommentAPI({
          cmtId: obj.com_id
        }) : await likeCommentAPI({
          cmtId: obj.com_id
        })
        this.$toast.success(obj.is_liking ? '取赞成功' : '点赞成功')
        obj.is_liking = !obj.is_liking
      } catch (e) {
        this.$toast.fail(obj.is_liking ? '取赞出错' : '点赞出错')
      }
    },
    // 滚动列表区域
    scrollIntoViewFn () {
      // ref获取元素不能跨文件
      // 这里获取元素表面上是跨文件了，
      // 实际上没有，因为所有的代码会被打包，放入同一个html文件中
      const el = document.querySelector('div.like-box')
      el.scrollIntoView({
        behavior: 'smooth'
      })
    },
    // 文本域的失焦事件
    blurFn () {
      setTimeout(() => {
        // 延时隐藏，异步效果
        this.isShow = true
      })
    },
    // 发布评论
    async publishFn () {
      if (!this.content) return
      try {
        // 同步到后台
        const resp = await publishCommentAPI({
          artId: this.$route.query.art_id,
          content: this.content
        })
        // 添加到数组的头部
        this.commentList.unshift(resp.data.new_obj)
        this.$toast.success('发布成功')
        // 总数量+1
        this.totalCount++
        // 内容清空
        this.content = ''
      } catch (e) {
        this.$toast.fail('发布出错')
      }
    },
    // 上拉触底加载更多
    pullUpLoadMoreFn () {
      this.getCommentListFn()
    }
  }
}
</script>

<style scoped lang="less">
.cmt-list {
  padding: 10px;
  .cmt-item {
    padding: 15px 0;
    + .cmt-item {
      border-top: 1px solid #f8f8f8;
    }
    .cmt-header {
      display: flex;
      align-items: center;
      justify-content: space-between;
      .cmt-header-left {
        display: flex;
        align-items: center;
        .avatar {
          width: 40px;
          height: 40px;
          background-color: #f8f8f8;
          border-radius: 50%;
          margin-right: 15px;
        }
        .uname {
          font-size: 12px;
        }
      }
    }
    .cmt-body {
      font-size: 14px;
      line-height: 28px;
      text-indent: 2em;
      margin-top: 6px;
      word-break: break-all;
    }
    .cmt-footer {
      font-size: 12px;
      color: gray;
      margin-top: 10px;
    }
  }
}
/*美化 - 文章详情 - 底部的评论页面 */
// 外层容器
.art-cmt-container-1 {
  padding-bottom: 46px;
}
.art-cmt-container-2 {
  padding-bottom: 80px;
}

// 发布评论的盒子 - 1
.add-cmt-box {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
  box-sizing: border-box;
  background-color: white;
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 46px;
  line-height: 46px;
  padding-left: 10px;
  .ipt-cmt-div {
    flex: 1;
    border: 1px solid #efefef;
    border-radius: 15px;
    height: 30px;
    font-size: 12px;
    line-height: 30px;
    padding-left: 15px;
    margin-left: 10px;
    background-color: #f8f8f8;
  }
  .icon-box {
    width: 40%;
    display: flex;
    justify-content: space-evenly;
    line-height: 0;
  }
}

.child {
  width: 20px;
  height: 20px;
  background: #f2f3f5;
}

// 发布评论的盒子 - 2
.cmt-box {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 80px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 12px;
  padding-left: 10px;
  box-sizing: border-box;
  background-color: white;
  textarea {
    flex: 1;
    height: 66%;
    border: 1px solid #efefef;
    background-color: #f8f8f8;
    resize: none;
    border-radius: 6px;
    padding: 5px;
  }
  .van-button {
    height: 100%;
    border: none;
  }
}
</style>
